Gents,
with your help i've built required multibody mesh with single (conformal) surface boundary between bodies, thanks for help and teaching!
Actually, i want use as loading top boundary surface not flat surface but the surface which close to the real sea bottom bathymetry (the image and cross-section find please attached). First attempt was not successful, look's like "Normal force" is not applicable for not flat boundary surface. Could you advice how to load such kind of boundary?
Thanks in advance!
Time dependent 3D Maxwell material viscoelastic Earth deformation
Re: Time dependent 3D Maxwell material viscoelastic Earth deformation
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Re: Time dependent 3D Maxwell material viscoelastic Earth deformation
I believe these are your options for boundary forces
Re: Time dependent 3D Maxwell material viscoelastic Earth deformation
Kevin, thank you for support,
then i've met iterations problem.
My machine is AMD Ryzen7 2700 eight core processor x16, Memory 32CiB, Ubuntu 20.04 2LTS 64bit.
After several efforts i found configuration:
Linear System Solver = Iterative
Linear System Iterative Method = GCR
Linear System Max Iterations = 3000
Linear System Preconditioning = BILU2
Linear System Convergence Tolerance = 0.001
which promised only several days to compute 21000 years of forcing to the sea bottom by water layer which increasing from 0 to 120 m of depth during that time.
Could somebody of society advise how estimate convergence tolerance if i want error of z-displacement not more than 1 cm? and determine how long time require calculate it.
Sincerely thanks
in advance.
then i've met iterations problem.
My machine is AMD Ryzen7 2700 eight core processor x16, Memory 32CiB, Ubuntu 20.04 2LTS 64bit.
After several efforts i found configuration:
Linear System Solver = Iterative
Linear System Iterative Method = GCR
Linear System Max Iterations = 3000
Linear System Preconditioning = BILU2
Linear System Convergence Tolerance = 0.001
which promised only several days to compute 21000 years of forcing to the sea bottom by water layer which increasing from 0 to 120 m of depth during that time.
Could somebody of society advise how estimate convergence tolerance if i want error of z-displacement not more than 1 cm? and determine how long time require calculate it.
Sincerely thanks
in advance.
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Re: Time dependent 3D Maxwell material viscoelastic Earth deformation
Hi
For standard elasticity I would recommend linear solver in style:
https://github.com/ElmerCSC/elmerfem/tr ... StabBoomer
But here it seems that you also solve for the pressure. What kind of block is the (4,4) block? Are the bubble degrees of freedom condensed away from the linear system?
The optimal strategy could be some kind of block preconditioning strategy. Like for the Stokes equation the system may be preconditioned such that using the true blocks for the velocity but an rough approximation of the schur complement for the pressure block (scaled mass matrix). This could be something similar but I'm not too familiar.
-Peter
For standard elasticity I would recommend linear solver in style:
https://github.com/ElmerCSC/elmerfem/tr ... StabBoomer
But here it seems that you also solve for the pressure. What kind of block is the (4,4) block? Are the bubble degrees of freedom condensed away from the linear system?
The optimal strategy could be some kind of block preconditioning strategy. Like for the Stokes equation the system may be preconditioned such that using the true blocks for the velocity but an rough approximation of the schur complement for the pressure block (scaled mass matrix). This could be something similar but I'm not too familiar.
-Peter
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Re: Time dependent 3D Maxwell material viscoelastic Earth deformation
A posting of the log file from the run my help provide some insight.
Re: Time dependent 3D Maxwell material viscoelastic Earth deformation
find please attached - sif, top part of the log and Lua
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- depthload.txt
- (471 Bytes) Downloaded 128 times
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- case.sif
- (5.7 KiB) Downloaded 128 times
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- current_sollog.txt
- (253.24 KiB) Downloaded 123 times
Re: Time dependent 3D Maxwell material viscoelastic Earth deformation
Peter, thank you for recommendations,raback wrote: ↑05 Oct 2021, 17:44 Hi
For standard elasticity I would recommend linear solver in style:
https://github.com/ElmerCSC/elmerfem/tr ... StabBoomer
But here it seems that you also solve for the pressure. What kind of block is the (4,4) block? Are the bubble degrees of freedom condensed away from the linear system?
The optimal strategy could be some kind of block preconditioning strategy. Like for the Stokes equation the system may be preconditioned such that using the true blocks for the velocity but an rough approximation of the schur complement for the pressure block (scaled mass matrix). This could be something similar but I'm not too familiar.
-Peter
sorry if i miss understood somethings,
i believe, i am using next applications described by:
Chapter6.2.2 from
https://www.nic.funet.fi/pub/sci/physic ... Manual.pdf
and paper
https://doi.org/10.5194/gmd-13-1155-2020
so, pressure is mandatory. Also, i do not use any stabilization techniques, look's like i need involve them?
i am a not good skilled beginner for Elmer, could you explain more detail for your question "What kind of block is the (4,4) block?"
Sincerely
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Re: Time dependent 3D Maxwell material viscoelastic Earth deformation
Youngs Modulus = 6.5844e+11
Viscosity = 2.7E+21
These are large numbers even for a 64 bit double precision computer. The problem is these values are divided by, use to divide, possibly very small numbers. Even though the 64b dp might be able to handle it it severely impacts the precision of the result, you start losing accuracy to the first decimal place. This potential accuracy issue could cause convergence issues.
Viscosity = 2.7E+21
These are large numbers even for a 64 bit double precision computer. The problem is these values are divided by, use to divide, possibly very small numbers. Even though the 64b dp might be able to handle it it severely impacts the precision of the result, you start losing accuracy to the first decimal place. This potential accuracy issue could cause convergence issues.
Re: Time dependent 3D Maxwell material viscoelastic Earth deformation
Hello,
If it helps, please find attached a similar case like the 2D test-case in 3D (runs on my gaming PC with 16 GB RAM and 6 core i5). Picture shows timestep of max. deformation: Mind, to first create mesh-file (keeping in mind, that one has to move from kilometres to metres):
(mind, my computer has 6 cores, change the last number accordingly to your hardware)
Best wishes,
Thomas
If it helps, please find attached a similar case like the 2D test-case in 3D (runs on my gaming PC with 16 GB RAM and 6 core i5). Picture shows timestep of max. deformation: Mind, to first create mesh-file (keeping in mind, that one has to move from kilometres to metres):
Code: Select all
gmsh -3 duallayer3d.geo
ElmerGrid 14 2 duallayer3d.msh -autoclean -scale 1000 1000 1000
ElmerGrid 2 2 duallayer3d -partdual -metiskway 6
Best wishes,
Thomas
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- duallayer3d.tgz
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Re: Time dependent 3D Maxwell material viscoelastic Earth deformation
Thomas,
Thank you for the test example. Especially, it is helpful for us to make comparisons between MATC and lua style expressions for writing functions.
Yours Sincerely,
Anil
Thank you for the test example. Especially, it is helpful for us to make comparisons between MATC and lua style expressions for writing functions.
Yours Sincerely,
Anil
Anil Kunwar
Faculty of Mechanical Engineering, Silesian University of Technology, Gliwice
Faculty of Mechanical Engineering, Silesian University of Technology, Gliwice